Feline Leukemia Virus (FeLV) Fact List

The Problem

Felines #1 Killer. FeLV infection occurs worldwide, with prevalence varying by location.
Feline leukemia virus is associated with the illness and death of more cats than any other infectious agent.
It is the largest epidemic to date among felines. Despite the availability of a vaccination, cats are susceptible
to this highly contagious disease. The public is largely unaware of the risks, the symptoms and danger of this disease.
Some cats have inherited this disease from their mother while others become infected by transmission.
This can occur between cats with casual contact, with normal grooming activities, sharing of water/ food bowls and litter boxes.
Unchecked this disease will continue to kill our feline companions.

The Solution

Increasing Community Awareness. There are ways to protect your cat from this disease by preventing exposure and by identifying infected cats before you expose them to other felines. The most effective way is to prevent exposure to FeLV-infected cats. Testing to identify infected cats is the mainstay of preventing transmission of FeLV. FeLV vaccination should not be considered a substitute for testing cats. The presence of the vaccination is misleading for cat owners, as it does not prevent transmission in all cases. The need for education regarding this silent killer of felines is essential to the disruption of the cycle of this deadly disease. In the future Marley's Cat Tales proposes to provide free feline leukemia testing and vaccinations to all non-profit animal organizations for our feline friends in our eighteen county service and surrounding outlying areas (Beaufort, Craven, Lenoir, Nash, Onslow, Pitt, Wake, Wilson, Gates, Pasquotank, Hertford, New Hanover, Chowan, Bertie, Orange, Carteret, Pamilco & Wayne). This provides a necessary service to assist pet owners in keeping healthy cats isolated from those that are infected.

FeLV Facts

What is Feline Leukemia Virus?
Feline Leukemia Virus is a virus that is specific to cats only. It is considered to be the most common cause of serious illness and death in domestic cats. It causes a breakdown in your cat's immune system causing your cat to become susceptible to many diseases, which it might otherwise be able to fight off. It cannot be transmitted to humans nor can it be transmitted to other species such as dogs.

What does a virus do to a cat?
In sum, once the virus gains entry (usually via saliva or mucus membranes) it will reproduce in the lymph tissue, which is your cat's first system of immune defense. Some cats are able to mount a successful immune response against it and defeat the virus at this stage. In cats that don't successfully destroy the virus here, the virus will then move into the bone marrow where red and white blood cells are produced. It may stay latent in the marrow for many years. After that it will attack other tissues, including possibly causing a breakdown in several stages of the immune response system.

How is Feline Leukemia Transmitted?
Feline Leukemia is transmitted via saliva, mucus, urine, feces and blood. This means mutual grooming and biting/fighting are the most likely methods of transmission, although sneezing; hissing, sharing food/water bowls and sharing litter boxes are also possible means of transmission.

Is there a vaccine?
Yes, there are several commercial vaccines available. These vaccines have been estimated to have a 75%-85% effectiveness (this means cats challenged with the virus will fight off infection 7-8 times out of ten). No vaccine, whether is be for cats, dogs or people, is 100% effective. However, feline leukemia vaccines aid prevention of infection of the disease and should be administered with your cat's other general vaccinations.

How is Feline Leukemia detected?
Your vet will do a blood test; there are two types of blood tests, the ELISA test and the IFA test, that can be performed. Some vets will automatically do one of the tests before vaccinating your cat to make sure it is not already positive for the virus. The ELISA is a test where the vet takes your cat's blood and tests it for color change. If the blood changes color then your cat has tested positive for the virus. False positives are not uncommon in this form of test, so if your cat tests positive it may be a good idea to have it re-tested in 2-3 months. "Light positives are where the treated blood only changes color slightly. This means your cat is infected with the virus, but the virus is not very active in its system. The second type of test is the IFA test where the blood work is tested to see if the virus is being produced in the bone marrow. If the second test is positive it is unlikely that your cat will ever test negative. See Testing for more information.

How long does a cat that tests positive have to live?
There is not a set time period for how long a Feline Leukemia cat will live. According to research, 83% of the feline leukemia positive cats do not live beyond 4 years and the other 17% are considered carriers of the disease, where the disease lies dormant and they can live for several years. However, this 17% can still spread the virus to other uninfected felines.

Although my cat has tested positive, it is healthy in all other respects. How can I prevent a Feline Leukemia related disease from becoming active in its system?
There is no sure way to keep your cat healthy. Eventually, a Feline Leukemia related disease would probably develop no matter what you do. However, one way in which a disease is likely to develop is if you stress your cat's system. If a cat's system is stressed, its body can't put as much energy into fighting off illnesses. Anything which is unsetting or unpleasant for your cat may stress it, such as going for very long times without water or food, overcrowding, movement to a new territory, territorial conflicts, or sending your cat to be boarded for long periods of time.

If my cat tests positive for Feline Leukemia Virus does this mean it has the disease, Feline Leukemia?
The virus was somewhat inappropriately named because it is different than the disease Feline Leukemia. A cat that tests positive for the virus will not necessarily contract the disease Feline Leukemia. However, cats that do test positive for the virus are more likely to catch any one of a number of disease including, but not limited to, leukemia, lymphoma or opportunistic infections.

Will I infect my healthy cat if I pet a Feline Leukemia positive cat, and then pet my cat?
No. Not unless you were to go immediately from one cat to another, and have wet saliva, urine or blood on your hand. Even then the chances would be slim. Feline Leukemia needs to be transferred via saliva, mucus, urine, feces and blood, and will not live long outside the host (infected cat).

If I don't get my cat vaccinated, what are its natural defenses against the virus?
According to research, neonatal kittens are 100% susceptible to catching the virus from one exposure. 8-week-old weanlings are 85% susceptible from one exposure. There is considerable debate over this issue, but most agree that 40% of cats exposed become immune, 30% become persistently infected (showing acute signs of a related-disease) and 30% become infected, but the virus is latent in their system.

How often do my cats need to be vaccinated?
After your cat has gone through its more elaborate set of kitten-shots, the Feline Leukemia vaccine should be given once a year. If you adopt an adult cat and don't know if it has been vaccinated for Feline Leukemia, start it immediately on its annual shots. If you are unsure if your adult cat needs to be vaccinated, talk to your vet.

If I get my cat vaccinated, isn't there a chance that it will catch the virus from the vaccine?
No. As of July 1992, all of the vaccines, which are approved for sale in the United States, are incapable of causing a positive Feline Leukemia result.

These signs may be a warning of a deadly feline virus:

Bite Wounds

Swollen Lymph Nodes

Gingivitis

Dehydration

Neurological Signs

Abscesses

Fever

Diarrhea

Vomiting

Weight Loss

Veterinarians have long considered feline leukemia hard to diagnose, but new research has identified symptoms and behaviors that indicate when infection is most likely, and when a cat should be tested. One in four cats with even one of these signs listed above is likely to test positive.

However, a cat with no symptoms may test positive for either virus. Cats most at risk are outdoor cats that fight, or share food and water with other cats, and cats in multi-cat households.

When a cat's behavior puts it at risk, or when a cat shows clinical signs, it makes sense to have your cat tested. Marley's Cat Tales suggests that you always have your cat tested from origination and annually for cat's protection and for fear of transmission to other felines.

If your cat tests positive...
A cat infected with Feline Leukemia Virus may continue to live happily for some time. Your veterinarian may recommend the following steps:

Keep your cat indoors to limit its exposure to other infections, and to prevent your cat from spreading its illness.

Keep your cat's environment as stress-free as possible, providing it with a comfortable place to rest, and limiting its interaction with people or other pets that may annoy it.